title: Changes in the structural composition and reactivity of Acer rubrum leaf litter tannins exposed to warming and altered precipitation: climatic stress-induced tannins are more reactive.
abstract: • Climate change could increase the frequency with which plants experience abiotic stresses, leading to changes in their metabolic pathways. These stresses may induce the production of compounds that are structurally and biologically different from constitutive compounds. • We studied how warming and altered precipitation affected the composition, structure, and biological reactivity of leaf litter tannins in Acer rubrum at the Boston-Area Climate Experiment, in Massachusetts, USA. • Warmer and drier climatic conditions led to higher concentrations of protective compounds, including flavonoids and cutin. The abundance and structure of leaf tannins also responded consistently to climatic treatments. Drought and warming in combination doubled the concentration of total tannins, which reached 30% of leaf-litter DW. This treatment also produced condensed tannins with lower polymerization and a greater proportion of procyanidin units, which in turn reduced sequestration of tannins by litter fiber. Furthermore, because of the structural flexibility of these tannins, litter from this treatment exhibited five times more enzyme (β-glucosidase) complexation capacity on a per-weight basis. Warmer and wetter conditions decreased the amount of foliar condensed tannins. • Our finding that warming and drought result in the production of highly reactive tannins is novel, and highly relevant to climate change research as these tannins, by immobilizing microbial enzymes, could slow litter decomposition and thus carbon and nutrient cycling in a warmer, drier world.
authors.affiliation: Entomology Soils & Plant Sciences, Clemson University, Clemson, SC 29634 USA.
authors.forename: Nishanth
authors.initials: N
authors.lastname: Tharayil
authors.affiliation: Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Vidya
authors.initials: V
authors.lastname: Suseela
authors.affiliation: Entomology Soils & Plant Sciences, Clemson University, Clemson, SC 29634 USA.
authors.forename: Daniella J
authors.initials: DJ
authors.lastname: Triebwasser
authors.affiliation: Natural Resources Canada, Pacific Forestry Centre, Victoria, BC V8Z 1M5 Canada.
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Preston
authors.affiliation: Applied Economic and Statistics, Clemson University, Clemson, SC 29634, USA.
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Gerard
authors.affiliation: Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA.|Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.|Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Dukes
mesh_terms: D031002:Acer / Q000378:metabolism*; D057231:Climate Change; D005419:Flavonoids / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010636:Phenols / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D025341:Principal Component Analysis; D011891:Rain; D017550:Spectroscopy, Fourier Transform Infrared; D013312:Stress, Physiological; D013634:Tannins / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
chemical_list: D005419:Flavonoids; D008563:Membrane Lipids; D010636:Phenols; D013634:Tannins; C000521:cutin